Vacuum suction

Which of these is a necessary condition for candle to burn?

• oxygen.

• carbon Dioxide

• light

Arrange the following in sequence :

A. Creation of vacuums.

B. Burning of oxygen

C. Generation of suction force between napkin and glass.

• A--B--C

• B--C--A

• A--C--B

On being trapped in an air tight cave, which of these is a life threatening way to enlighten it

• Fire

• Battery run lamp.

In the same experiment, if the glass base and napkin is replaced by a tray of water what will be your observation

• water will rise up inside the glass.

• water will turn black.

• level of water will remain same.

Why do you think the napkin is soaked in water ?

• to prevent the base from burning

• to reduce friction between glass and base

• to make the contact air tight